The ferries and floating bridges are mainly intended to allow military vehicles to cross a stream or a river out of any bridge or other permanently set up ferry system. The applications may also be civil, after floods or inundations for example or for crossing a river without a permanent structure and in particular to allow the passage of heavy building site or crash rescue vehicles for example.
The most particularly targeted vehicles are endless track or wheeled vehicles of average mass able to weigh up to 30 to 60 tons.
The modules constituting the ad hoc ferry or bridge may in particular be brought to the required crossing point and assembled.
Generally, a ferry or floating bridge is made from one or several floatation tank(s), possibly motorized, and designed to support a track for the circulation of the vehicles on the ferry or the bridge.
In a complementary manner, said bridge or ferry may be terminated at one or both of its ends by an access ramp, usually foldable, or angularly adjustable, allowing the loading and unloading of the transported vehicles. Advantageously however, the ferry or bridge will be ambidromic.
In the case of a floating bridge assembly, the number of assembled modules will depend on the distance to cross and the floatation features of the floatation tanks. In the case of a transport ferry assembly, the number of assembled modules will obviously depend on the vehicles to be transported as well as their load based on the floatation features of the tanks.
An autonomous module containing the set of elements required for assembling the ferry or the floating bridge to be made does not exist, except for the amphibious and motorized autonomous vehicles such as the Forward Crossing Apparatuses (FCA). Such machines are not easily movable away from their point of attachment, in particular, by air and remain relatively expensive since they have their own amphibious motor system also requiring more important maintenance.
As regards transportable systems, there are ferries and floating bridges made from boats on which treadways, elements constituting the final haulage road, are set up transversally to the boats.
The assembling of a ferry or floating bridge hence currently requires the transport of said boats, treadways, motors to be set up on the boats, etc. . . . namely numerous scattered components usually rendering difficult a rapid rooting on site.
Moreover, the different elements being separate, the assembling requires a relatively long time and remains complex, the weight of each element having to be carried by a man should not exceed the military limits.